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"I mean, this is the highest of the high alert; clearly everyone here realizes that she, assuming she is with Khalil Tatum, is probably in real danger," said Lt. Bill Alexander, spokesman for the Prince George's County Police.

Tatum lived in this two-story apartment building along N Street in Southeast, and a mail carrier told ABC 7 that the 51-year-old moved in about six months ago:

"You know, he seemed like he had it all together."

Juvia Bush lives directly below Tatum, and while she never saw young Rudd, she often ran into Tatum with his now deceased wife, Andrea.

"They appeared very happy to me, that's why it was a complete shocker to me because they seemed like the kind of couple that was close-knit," she said.

While investigators won’t say exactly what evidence links Tatum to his wife’s murder, they are confident that he pulled the trigger, and are worried he could act again.

"So we're imploring our community, the people out there, please be on watch," said Lt. Alexander. "If you see Khalil Tatum or anyone you think may be him, particularly with a young girl, any tidbit of information could be that single bit of information we need to get this guy into custody."

Several reporters have inquired about the activation of the Amber Alerts in the case of missing 8-year-old Relisha Rudd.

I am very satisfied with the efforts of our regional partners to publicize this case. We appreciate the overwhelming support from the media and government agencies such as transportation agencies, fusion centers, state and local law enforcement agencies including Maryland and Virginia. This has resulted in saturation coverage, numerous alerts being issued by phone and text, highway alerts being activated, and tips received from as far away as Chesterfield, Virginia.

At this time, all known vehicles potentially associated with this case have been recovered. We will continue to share information as appropriate as it is developed. The urgent priority is to locate this girl.